While it is possible to register copyright in a work through the Canadian Intellectual Property Office, registration is not necessary for a work to be considered protected. Original literary, dramatic, musical and artistic works, as well as sound recordings, performances, and communication signals, are automatically protected by copyright. Facts, ideas and data, however, cannot be copyrighted. Typically, 'fixation', either on paper or as a digital file, is a requirement for copyright to subsist in a work. The fixation requirement is in keeping with the principle that ideas themselves may not be copyrighted, only the expression of the ideas. Notable exceptions to the fixation rule include a 'performer’s performance', such as a play or musical performance that are not in a fixed form (that is, recorded) but are nonetheless covered by copyright.